In studies on the mechanism of inhibition by HCHO of energy- transduction processes, particular attention will be given to the cytochrome b-cytochrome c segment of the respiratory chain, to determine whether the sensitive site can be "tagged" by using H14CHO and boron- hydride reduction. With regard to transport mechanisms and interconversions of 1-C derivatives in phosphorylating mitochondria, recent analyses in our laboratory indicated that metabolic pathways and enzymes utilizing 1-C compounds at the oxidation level of formaldehyde can be distiguished in the presence of an agent such as aminoguanidine. In extending these studies, it remains to be determined whether there is also an allosteric influence on the initial dehydrogenation reactions yielding the 1-C unit(s) and whether the aminoguanidine can participate directly in 1-C transfer reactions. Concerning the role of Mg ions and adenine nucleotides in the control of N-methyl oxidation attention will be given to the possibility that the nucleotides prevent the efflux of glycine from the inner matrix of the mitochondria. In extending our studies on inducible flavin and folate biosynthesis in bacteria grown solely on N-methyl substrates, chromatography will be employed to separate and identify the one-carbon derivatives of the tetrahydrofolate whose concentrations are elevated in these organisms. Ralationships between the pathways of biosynthesis of flavins and pigment in the bacteria on sarcosine will also be assessed. The cells will be culture on (14)CH3-N-CH2C00H, and CH3-N(14)CH2COOH, and CH3NH-CH2-(14)COOH and rates, extent, and positions of incorporation of C14 into both peptide-pigments and the flavin-peptides will be determined.